Condition variable usage, zp->r_{rd,wr}_cv

The following incorrect usage of cv_broadcast() was caught by
code inspection.  The cv_broadcast() function must be called
under the associated mutex to preventing racing with cv_wait().

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

diff --git a/module/zfs/zfs_rlock.c b/module/zfs/zfs_rlock.c
index 208de10..c278035 100644 (file)
--- a/module/zfs/zfs_rlock.c
+++ b/module/zfs/zfs_rlock.c
@@ -486,7 +486,7 @@ zfs_range_unlock_reader(znode_t *zp, rl_t *remove, list_t *free_list)
         */
        if (remove->r_cnt == 1) {
                avl_remove(tree, remove);
-               mutex_exit(&zp->z_range_lock);
+
                if (remove->r_write_wanted)
                        cv_broadcast(&remove->r_wr_cv);
 
@@ -530,7 +530,6 @@ zfs_range_unlock_reader(znode_t *zp, rl_t *remove, list_t *free_list)
                        }
                }
 
-               mutex_exit(&zp->z_range_lock);
                kmem_free(remove, sizeof (rl_t));
        }
 }
@@ -554,7 +553,6 @@ zfs_range_unlock(rl_t *rl)
        if (rl->r_type == RL_WRITER) {
                /* writer locks can't be shared or split */
                avl_remove(&zp->z_range_avl, rl);
-               mutex_exit(&zp->z_range_lock);
                if (rl->r_write_wanted)
                        cv_broadcast(&rl->r_wr_cv);
 
@@ -569,6 +567,7 @@ zfs_range_unlock(rl_t *rl)
                 */
                zfs_range_unlock_reader(zp, rl, &free_list);
        }
+       mutex_exit(&zp->z_range_lock);
 
        while ((free_rl = list_head(&free_list)) != NULL) {
                list_remove(&free_list, free_rl);
@@ -599,11 +598,13 @@ zfs_range_reduce(rl_t *rl, uint64_t off, uint64_t len)
        mutex_enter(&zp->z_range_lock);
        rl->r_off = off;
        rl->r_len = len;
-       mutex_exit(&zp->z_range_lock);
+
        if (rl->r_write_wanted)
                cv_broadcast(&rl->r_wr_cv);
        if (rl->r_read_wanted)
                cv_broadcast(&rl->r_rd_cv);
+
+       mutex_exit(&zp->z_range_lock);
 }
 
 /*